1. Field of the Invention
The present general inventive concept relates to an image forming apparatus and an image forming method, and more particularly to an image forming apparatus to convert color printing data into mono printing data when any one of colors of developer is used up, and an image forming method thereof.
2. Description of the Related Art
In general, an image forming apparatus forms a latent image on an image carrying body, charged at predetermined electric potential, through exposure and develops the latent image with a developer having a predetermined color. Then, the developed image is transferred and fused on a print medium, thereby printing an image.
As network technology becomes advanced, the image forming apparatus has recently been used while being connected to a plurality of host systems through network. Further, to process a plurality of image data transmitted from the plurality of host systems, the image processing apparatus has increased in printing speed.
FIG. 1 is a schematic diagram of a printing procedure in a conventional image forming apparatus. As illustrated therein, the conventional image forming apparatus (P) receives printing signals from a plurality of host systems h1, h2, h3 via communications network N and converts image data of the printing signals into printing data to be printable. The converted printing data forms a queue of printing jobs (pj) and is then printed on a print medium in sequence.
However, in the conventional image forming apparatus, if any one of colors of developer remains less than the amount required for color printing, the printing jobs are not smoothly printed. In other words, if a magenta developer is substantially used up while the printing job for first printing data a in printing job queue pj is printed as illustrated in FIG. 1, the color printing for second color printing data b may not be performed as desired.
At this time, the conventional image forming apparatus informs a user that the magenta developer is used up and allows a user to select whether or not to cancel the printing job for the second color printing data b being processed and whether to change the color printing to mono printing or not.
Meanwhile, there has been a problem that the printing job for third color printing data c following that for the second color printing data b may be delayed until the printing job for the second color printing data b is completed. However, a user of a third host system that outputs the printing signal for the third color printing data c cannot know why the printing job for the third color printing data c is delayed.
Further, even though a user of a second host system cancels the printing job for the second color printing data b, the printing data converted from the image data is not printed and still remains in a memory, thereby wastefully occupying the memory.
Also, when a user wants the second color printing data b, of which the printing job is canceled, to be printed as a mono image in one color such as black, the converted color printing data is unusable for the image forming apparatus and thus deleted. Accordingly, the host system has to output a new printing signal for the mono image to the image forming apparatus. If mono image data of the new printing signal is converted into fourth printing data b, the fourth printing data b is printed after all printing jobs waiting to be printed are completed, thereby making the user wait for a relatively long time.